On 2018/10/17 10:19, Jaegeuk Kim wrote:
> On 10/17, Chao Yu wrote:
>> Hi Jaegeuk, Jens,
>>
>> On 2018/10/17 3:23, Jaegeuk Kim wrote:
>>> Thanks Jens,
>>>
>>> On top of the patch killing the dead code, I wrote another one to detect
>>> the idle time by the internal account logic like below. IMHO, it'd be
>>> better to decouple f2fs with other layers, if possible.
>>>
>>> Thanks,
>>>
>>> >From 85daf5190671b3d98ef779bdea77b4a046658708 Mon Sep 17 00:00:00 2001
>>> From: Jaegeuk Kim <[email protected]>
>>> Date: Tue, 16 Oct 2018 10:20:53 -0700
>>> Subject: [PATCH] f2fs: account read IOs and use IO counts for is_idle
>>>
>>> This patch adds issued read IO counts which is under block layer.
>>
>> I think the problem here is, in android environment, there is multiple
>> kinds of filesystems used in one device (emmc or ufs), so, if f2fs only be
>> aware of IOs from itself, still we can face IO conflict between f2fs and
>> other filesystem (ext4 used in system/... partition), it is possible when
>> we are trigger GC/discard intensively such as in gc_urgent mode, user can
>> be stuck when loading data from system partition.
> 
> IMO, we don't need to worry about gc_urgent too much, since it will be set at

For most of the time, it's okay, in android idle time (IIRC, in middle
night, charging, screen shutdowns for a while) can be broken by user who
has bad habit that using cell phone in middle night randomly.... then user
operation can be stuck due to IO busy storage.

> the given android idle time. Other than that, I think it won't trigger GC and
> discard too frequently which would be able to affect /system operations.

How about considering low-end products? since performance of storage device
is real bad, handling discard/read IO in /data can affect /system operations.

> The new interface would be nice to have, but give more complexity on 
> backporting
> work in old kernels and newer as well across the layers.

Yes, that's a problem.

BTW, we just encounter 'GC not work' problem in product, I guess that's due
to is_idle()'s problem, let's try to confirm the root cause.

Thanks,

> 
>>
>> So I guess the better way to avoid this is to export IO busy status in
>> block layer to filesystem, in f2fs, we can provider effective service in
>> background thread at real idle time, and will not impact user.
>>
>> Any thoughts?
>>
>> Thanks,
>>
>>>
>>> Signed-off-by: Jaegeuk Kim <[email protected]>
>>> ---
>>>  fs/f2fs/data.c  | 24 ++++++++++++++++++++++--
>>>  fs/f2fs/debug.c |  7 ++++++-
>>>  fs/f2fs/f2fs.h  | 22 ++++++++++++++++------
>>>  3 files changed, 44 insertions(+), 9 deletions(-)
>>>
>>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>>> index 8952f2d610a6..5fdc8d751f19 100644
>>> --- a/fs/f2fs/data.c
>>> +++ b/fs/f2fs/data.c
>>> @@ -52,6 +52,23 @@ static bool __is_cp_guaranteed(struct page *page)
>>>     return false;
>>>  }
>>>  
>>> +static enum count_type __read_io_type(struct page *page)
>>> +{
>>> +   struct address_space *mapping = page->mapping;
>>> +
>>> +   if (mapping) {
>>> +           struct inode *inode = mapping->host;
>>> +           struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>>> +
>>> +           if (inode->i_ino == F2FS_META_INO(sbi))
>>> +                   return F2FS_RD_META;
>>> +
>>> +           if (inode->i_ino == F2FS_NODE_INO(sbi))
>>> +                   return F2FS_RD_NODE;
>>> +   }
>>> +   return F2FS_RD_DATA;
>>> +}
>>> +
>>>  /* postprocessing steps for read bios */
>>>  enum bio_post_read_step {
>>>     STEP_INITIAL = 0,
>>> @@ -82,6 +99,7 @@ static void __read_end_io(struct bio *bio)
>>>             } else {
>>>                     SetPageUptodate(page);
>>>             }
>>> +           dec_page_count(F2FS_P_SB(page), __read_io_type(page));
>>>             unlock_page(page);
>>>     }
>>>     if (bio->bi_private)
>>> @@ -464,8 +482,8 @@ int f2fs_submit_page_bio(struct f2fs_io_info *fio)
>>>  
>>>     __submit_bio(fio->sbi, bio, fio->type);
>>>  
>>> -   if (!is_read_io(fio->op))
>>> -           inc_page_count(fio->sbi, WB_DATA_TYPE(fio->page));
>>> +   inc_page_count(fio->sbi, is_read_io(fio->op) ?
>>> +                   __read_io_type(page): WB_DATA_TYPE(fio->page));
>>>     return 0;
>>>  }
>>>  
>>> @@ -595,6 +613,7 @@ static int f2fs_submit_page_read(struct inode *inode, 
>>> struct page *page,
>>>     }
>>>     ClearPageError(page);
>>>     __submit_bio(F2FS_I_SB(inode), bio, DATA);
>>> +   inc_page_count(F2FS_I_SB(inode), F2FS_RD_DATA);
>>>     return 0;
>>>  }
>>>  
>>> @@ -1593,6 +1612,7 @@ static int f2fs_mpage_readpages(struct address_space 
>>> *mapping,
>>>             if (bio_add_page(bio, page, blocksize, 0) < blocksize)
>>>                     goto submit_and_realloc;
>>>  
>>> +           inc_page_count(F2FS_I_SB(inode), F2FS_RD_DATA);
>>>             ClearPageError(page);
>>>             last_block_in_bio = block_nr;
>>>             goto next_page;
>>> diff --git a/fs/f2fs/debug.c b/fs/f2fs/debug.c
>>> index 026e10f30889..139b4d5c83d5 100644
>>> --- a/fs/f2fs/debug.c
>>> +++ b/fs/f2fs/debug.c
>>> @@ -55,6 +55,9 @@ static void update_general_status(struct f2fs_sb_info 
>>> *sbi)
>>>     si->max_vw_cnt = atomic_read(&sbi->max_vw_cnt);
>>>     si->nr_wb_cp_data = get_pages(sbi, F2FS_WB_CP_DATA);
>>>     si->nr_wb_data = get_pages(sbi, F2FS_WB_DATA);
>>> +   si->nr_rd_data = get_pages(sbi, F2FS_RD_DATA);
>>> +   si->nr_rd_node = get_pages(sbi, F2FS_RD_NODE);
>>> +   si->nr_rd_meta = get_pages(sbi, F2FS_RD_META);
>>>     if (SM_I(sbi) && SM_I(sbi)->fcc_info) {
>>>             si->nr_flushed =
>>>                     atomic_read(&SM_I(sbi)->fcc_info->issued_flush);
>>> @@ -371,7 +374,9 @@ static int stat_show(struct seq_file *s, void *v)
>>>             seq_printf(s, "  - Inner Struct Count: tree: %d(%d), node: 
>>> %d\n",
>>>                             si->ext_tree, si->zombie_tree, si->ext_node);
>>>             seq_puts(s, "\nBalancing F2FS Async:\n");
>>> -           seq_printf(s, "  - IO (CP: %4d, Data: %4d, Flush: (%4d %4d 
>>> %4d), "
>>> +           seq_printf(s, "  - IO_R (Data: %4d, Node: %4d, Meta: %4d\n",
>>> +                      si->nr_rd_data, si->nr_rd_node, si->nr_rd_meta);
>>> +           seq_printf(s, "  - IO_W (CP: %4d, Data: %4d, Flush: (%4d %4d 
>>> %4d), "
>>>                     "Discard: (%4d %4d)) cmd: %4d undiscard:%4u\n",
>>>                        si->nr_wb_cp_data, si->nr_wb_data,
>>>                        si->nr_flushing, si->nr_flushed,
>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>> index 156e6cd2c812..5c80eca194b5 100644
>>> --- a/fs/f2fs/f2fs.h
>>> +++ b/fs/f2fs/f2fs.h
>>> @@ -950,6 +950,9 @@ enum count_type {
>>>     F2FS_DIRTY_IMETA,
>>>     F2FS_WB_CP_DATA,
>>>     F2FS_WB_DATA,
>>> +   F2FS_RD_DATA,
>>> +   F2FS_RD_NODE,
>>> +   F2FS_RD_META,
>>>     NR_COUNT_TYPE,
>>>  };
>>>  
>>> @@ -1392,11 +1395,6 @@ static inline unsigned int f2fs_time_to_wait(struct 
>>> f2fs_sb_info *sbi,
>>>     return wait_ms;
>>>  }
>>>  
>>> -static inline bool is_idle(struct f2fs_sb_info *sbi, int type)
>>> -{
>>> -   return f2fs_time_over(sbi, type);
>>> -}
>>> -
>>>  /*
>>>   * Inline functions
>>>   */
>>> @@ -1787,7 +1785,9 @@ static inline void inc_page_count(struct f2fs_sb_info 
>>> *sbi, int count_type)
>>>     atomic_inc(&sbi->nr_pages[count_type]);
>>>  
>>>     if (count_type == F2FS_DIRTY_DATA || count_type == F2FS_INMEM_PAGES ||
>>> -           count_type == F2FS_WB_CP_DATA || count_type == F2FS_WB_DATA)
>>> +           count_type == F2FS_WB_CP_DATA || count_type == F2FS_WB_DATA ||
>>> +           count_type == F2FS_RD_DATA || count_type == F2FS_RD_NODE ||
>>> +           count_type == F2FS_RD_META)
>>>             return;
>>>  
>>>     set_sbi_flag(sbi, SBI_IS_DIRTY);
>>> @@ -2124,6 +2124,15 @@ static inline struct bio *f2fs_bio_alloc(struct 
>>> f2fs_sb_info *sbi,
>>>     return bio_alloc(GFP_KERNEL, npages);
>>>  }
>>>  
>>> +static inline bool is_idle(struct f2fs_sb_info *sbi, int type)
>>> +{
>>> +   if (get_pages(sbi, F2FS_RD_DATA) || get_pages(sbi, F2FS_RD_NODE) ||
>>> +           get_pages(sbi, F2FS_RD_META) || get_pages(sbi, F2FS_WB_DATA) ||
>>> +           get_pages(sbi, F2FS_WB_CP_DATA))
>>> +           return false;
>>> +   return f2fs_time_over(sbi, type);
>>> +}
>>> +
>>>  static inline void f2fs_radix_tree_insert(struct radix_tree_root *root,
>>>                             unsigned long index, void *item)
>>>  {
>>> @@ -3116,6 +3125,7 @@ struct f2fs_stat_info {
>>>     int free_nids, avail_nids, alloc_nids;
>>>     int total_count, utilization;
>>>     int bg_gc, nr_wb_cp_data, nr_wb_data;
>>> +   int nr_rd_data, nr_rd_node, nr_rd_meta;
>>>     unsigned int io_skip_bggc, other_skip_bggc;
>>>     int nr_flushing, nr_flushed, flush_list_empty;
>>>     int nr_discarding, nr_discarded;
>>>
> 
> .
> 



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